A search engine is a computer program that helps a user to locate information. Using a search engine, a user can enter one or more search query terms and obtain a list of resources that contain or are associated with subject matter that matches those search query terms. While search engines may be applied in a variety of contexts, search engines are especially useful for locating resources that are accessible through the Internet. Resources that may be located through a search engine include, for example, files whose content is composed in a page description language such as Hypertext Markup Language (HTML). Such files are typically called pages. One can use a search engine to generate a list of Universal Resource Locators (URLs) and/or HTML links to files, or pages, that are likely to be of interest.
The search engine typically has an interface allowing users to specify search criteria and an interface displaying the search results. Typically, the search engine orders the search results prior to presenting the search results interface to the user. The order usually takes the form of a “ranking,” where the document with the highest ranking is the document considered most likely to satisfy the interest reflected in the search criteria specified by the user. The user is sent one (or more) search results pages based on the ranking. However, the user must still spend considerable time and effort processing the search results to determine whether the search query produced adequate search results. If the user is not satisfied with the results, the user forms a new search query and repeats the process.
Thus, the search process is often an iterative task in which the user forms a search query, determines whether the voluminous search results are adequate, and then re-formulates the search query, if needed. Therefore, the user experience with search engines is often frustrating and time consuming.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.